Tooth for excavators



June 14, 1960 E. D. LATTNER 2,940,192

TOOTH FOR EXCAVATORS Filed Sept. 12, 1957 2 Sheets-Sheet 1 Bab/"3: it I 3:

39 INVENTOR.

34 .26 2 34 'BW/A/ 0. LA7'7'NEE 587c5, 724K 2 MBea 4 TTOENEYS TOOTH FOR EXCAVATORS Erwin D. Lattner, Geneva, Ohio, assign-or to The Cleveland Trencher Company, Cleveland, Ohio, a corporation of Ohio Filed Sept. 12, 1957, Ser. No. 683,521

3 Claims. 31-142 This invention relates to excavating teeth and more particularly to those having replaceable tips and adapted for use on the cutting edges of buckets of power-driven excavating machines and the like.

Excavating machines used for ditching or trenching are intended to produce an excavation of a definite size, the width of the excavation being generally governed by the size of the scoops or buckets used to remove the material being dug. Machines of this type are usually provided with teeth set around the lips of the buckets of the excavating unit. Such teeth are usually held in place by bolts or other suitable fastening means and are generally arranged so as to be removable from the buckets.

In service these teeth wear and become ineflicient in the digging of the right size of trench and thus the replacement of the teeth is relatively frequent.

in the past, such teeth have sometimes been provided with separable cutting tips thereby obviating the necessity of replacing the whole tooth, when the cutting edge thereof becomes Worn and no longer functions elfectively. Such separable tooth construction has generally been of the socket type where one of the portions of the tooth comprises a female section and the other portion comprises a male section adapted to be received in holding relationship in the female section. Bolts, tapers, or staking, or the combination thereof, have generallybeen used to hold the separable sections of the teeth together for service operation.

The separable cutting tips of such teeth have heretofore generally been either welded or forged to produce the combination of a hardened cutting edge and a Softer material in the socket or holding portion thereof. In the case of forged cutting tips, a difiicult and expensive difierential hardening treatment is required. In addition past arrangements have not been entirely satisfactory in holding the separable parts of the teeth together. excavating unit of a trenching machine is subject to considerable Wear, impact and vibration, and many times the prior art separable tooth arrangements have become inseparable because of the distortion of the holding means thereby defeating the purpose of the separable tooth construction, or have become loose because of the failure of the fastening arrangement, resulting in loss of cutting tips and the expensive and time consuming replacement thereof. v

The present invention provides a separable digging tooth arrangement in which a hardened, removable cutting tip portion is positivelyheld in assembled relationship with a shank portion of the tooth by means of a comparatively ductile band or collar member and wherein the band member and the shank portion have complementary tapered surfaces thereon which lock the separable parts of the tooth together; Moreover, the present invention provides a structural arrangement including shoulders on the shank portion of the tooth whereby the band and interlocked-cutting tip may be rapidly moved out of locking relationship with the shank of the tooth by means of a tool, and the cutting tip thereafter replaced sent 0 2 by a new tip, and using the same band may be quickly reassembled into locking relationship with the shank of the tooth, to provide an eificient and convenient method of changing worn or damaged cutting tips on the teeth '5 .of the excavating unit.

It is therefore an object of the present invention to providea digging tooth for an excavating machine which has a removable cutting tip and which includes a novel band and taper arrangement for locking the tip to the base portion of the tooth.

Another object of the invention is to provide a digging tooth of the latter mentioned type in which the cutting tip will stay in place without the use of auxiliary fastening devices, but which incorporates structure for providing for rapid removal and replacement of the cutting tip when desired.

A more specific object of the invention is to provide an excavating tooth comprising a base portion and a shank portion extending forwardly from the base portion with a v hardened, separable cutting tip disposed in abutting relationship with the shank portion andextending forwardly of the latter, and also including a relatively ductile retaining band element coacting with the cutting tip portion and the shank portion of thetooth to hold. the 25. latter portions together in locked relationship, irrespective of vibration and impact to which the tooth is subjected in service.

Another object of the invention is to provide an excavating tooth of the latter described type wherein the retaining band and the shank portion of the tooth have complementary tapered surfaces adapted for wedging co- Y action for locking the separable portions of the tooth together.

A still further object of the invention is to provide a rooter tooth of the above described type wherein the retaining band and cutting tip elements are secured together as a unit to facilitate assembly and disassembly of the parts of the tooth.

Other features and advantages of the invention will be apparent from the following description taken in conjunction with the accompanying drawings wherein:

Fig. l is a fragmentary view of a portion of an excavating wheel having an excavating bucket thereon provided with rooter teeth of the instant invention;

,Fig. 2 is a perspective view of the improved excavating tooth;

' Fig. 3 is a longitudinal, vertical sectional view of the tooth illustrated in Fig. 2;

Fig. 4 is an enlarged sectional view taken generally along line 4-4 of Fig. 3, portions of the tooth being removed in the interests of clarity;

Fig. 5 is an enlarged sectional view similar to Fig. 4 but taken generally along line 55 of Fig. 3;

Fig. 6 is a top plan view of the separable cutting tip of the digging tooth of the invention;

Fig. 7 is a side elevational view of the cutting tip illustrated in Fig. 6; Fig. 8 is a side elevational view of the retaining band element of the digging tooth; 6 Fig. 8a is an end elevational view taken generally along line 8a--8a of Fig. 8;

Fig. 9 is a side elevational view illustrating a modification of the invention wherein the relative positions of the cuttng tip, retainingband and shank of the tooth base portion are reversed from that shown in Figs. 2 and 3;

Fig, 9a is a vertical sectional view taken generally along line 9a9a of Fig. 9; V

Fig. 10 is a side elevational view illustrating another modification of the invention wherein the retaining band 'or collaris secured to the cutting tipelement'to provide a-unit-which may be quickly-assembled and .disassembled from the shank portion of the tooth proper;

Fig. a is an endelevational view takengenerally along line 1041-1011 of Fig. 10;

Fig. 11 is a longitudinal, vertical, partially sectioned view generally similar to Fig. 3, yet illustrating a further modification of the inventionwherein means is provided for staking theretainingfband element-to the shank portion of the tooth for positively 'insuringnon loosening of the cutting tip or the tooth with respectto theother portions thereof;

Fig. 12 is a side elevational view of -theftoo'th aillustrated in Fig. 2, andsh owing the tool;for"rapidly'disv 4 operational characteristics of the latter described arrangement will hereinafter be more thoroughly discussed.

The front surface 38 of collar 30 is adapted for engagement with the aforementioned shoulders 28 on the cutting tip element 26 of the tooth while the rearwardly facing surface 40 of the collar is engageable with lip 32 on cutting element 26 of the tooth. The body portion 26b of tip element 26isTofsubstantia1ly the same width as the lower, portion .oftheshankreceiving passageway in collar member 30. 'It will be seen therefore that when the'cutting element 26 is in:assembled position With'shank 22-and collar 30, the'cutting element ispos'itivlysecured Referringinpa rticuIar to 'Figsl 1 to' 8a inclusive" of thedrawings, there is indicated at 10 (Fig. 1) a portion of an excavating iwheel provided with excavating buckets, one of whichis indicated at 12. The machine itself may be of the type shown in United States Patent No. 2,280,-

the forward edge ,of the excavating buckets will engage the material being excavated;

The improved-rooter or digging tooth 16 is shown as being applied to the bucket 12 by bolts or rivets 17 which pass through suitable openings 19 in the tooth base 121 and through aligned openings in the wall of the bucket 12. The tooth base 21 has a forwardly extending shank portion 22 connected thereto and extending angularly therefrom as" can be best seen in Fig. 3 ofthe drawings.

Base. portion 21 comprises a pair of transversely spaced shoulders 24 disposed on opposite sides of the shank portion 22,g enerally adjacent the inner end of the latter.

'Shoulders 24 are adapted for use in disassembling cutting tip member 26 of the tooth and for replacement thereof, as will hereinafter be more thoroughly discussed.

Cutting tip 26 of the tooth comprises a hardened platef like element having a forward or outer head portion 26a and a rearward or inner body portion 26b. The top surface of the head portion 26a is sloped or beveled downwardly as 781L271) improve the cutting characteristics of V the tip. A pair ofishoulders 28 are disposed on the head portion'26a adjacent the forward end of body portion 26b of the tip and are adapted for engagement with the front end surface of the retaining band member 30 when in assembled relationship with the other parts of the tooth 1 construction. The rearward end of the tip 26 is provided with a depending lip or flange 32 adapted to cooperate with the rear end surface of band member 30 to' main I tain the tip in predetermined assembled relationship with respect to the band and the base portion of the'tooth. It will be understood that the separable tip may be effectively cut, punched or sheared from steel plate and may be easily heat-treated to provide an economically desirable, separable cutting tip arrangement.

The retaining band or collar element 30 is of elongated tunnel-like configuration and comprises a relatively flat bottom wall '34 and a generally arcuate-like upper wall 36 connected to bottom wall 34 at opposite'sides thereof. As' can be best seen from Figs. 8 and 8a of the drawing, the inner surface 36a of the generally central section of upper wall '36 slopes downwardly in' a forward direction to provide a tapered abutment face adapted for'surfa'ceito-surface wedging engagement with a complementary tapered abutmentface '37 (Fig. 3) on the shank 22 of I basel'portion 21 of the toothassembly. In addition 'the inner side s'urfaces 36b of wall 36 generally converge in anu ward direction, with respect to one another'an'd to the longitudinal, vertical center plane of the band 30.

Surfaces 361; are adapted for wedging coaction with comto the collar 30 against relative movement 'in a lengthwise as well as in atransverse direction. a a

' 'When'the various parts of the separable tooth arrangement are in assembled condition, as shown inFig. 2 of the drawings, the top surface 42 of tip element 26 is in flat surface-to-surface engagement with the generally planar underface 44 (Fig. 3). of the shank portion 22 of the tooth proper. Itwvill be seen that surface 42'is of such longitudinal extent and transverse width as to provide'fiat surface-to-surface engagement with substantially the full area of surface '44 on the shank, to thereby stabilize the tip and shank assembly and insure a generally equalized distribution of stress during digging operations.

- It will also be seen that the retaining band member 'is positioned rearwardly of the forward extremities of both the cutting tip element 26 and the shank portion 22 whilegstill engaging a substantial portion of the lengthwise extent of the shank, to thereby provide as much support as possible for the cutting tip but not interfering with the penetration of the tip into the material to be excavated,

'during digging operations.

The tapered surfaces 36a and 36b on hand 30 engage in wedging coaction with the complementary tapered surfaces 37 and 39 on the shank 22'when the band and as- ;sociated cutting tip 26 are slipped, over the shank to thereon slips behind surface 40 on the band member,

then moving the band and tip assembly along the shank until full wedging engagement between the tapered a hammer or achisel may then be applied to the band 1 member to positively drive the tip and band assembly lines in Fig. 12 of the drawings to the position illustrated in phantom lines to thereby force the band and associated cutting tip 26 outwardly along the shank from the tooth base. -It will be seen that the Wedge legs 46a have full bearing engagement'with thediagonally sloping shoulders 24 on the base portion21of the tooth 'to effectively move the cutting tip out of assembled relationship. It will also be noted that the point of engagement plenientary sloped side surfaces 39 (Figs. 4 e 5]) on the shank portion 22 of the tooth. The function and-'76 l sa icn fo s p t n the p nd a p ns of the eet A feature of the invention is that the retaining band member 30 may be used again and again in a tooth assembly, the only part needing to be replaced being the cutting tip element 26. This is made possible by having the tapered surfaces 36a, 36b and 37, 39 on respectively the retaining band and the shank portion of the tooth so constructed and arranged that the elastic limit of the material of the retaining band is never exceeded when the band and tip assembly is applied to the shank portion of the tooth. It will be seen, therefore, that the invention provides an effectively operating and economically desirable tooth requiring the replacement of only the comparatively low cost cutting tip element.

In the embodiment of the invention shown, the locking surface 36a of the generally central portion of the retaining band element and the top locking surface 37 of the shank portion 22 of the tooth base are tapered forwardly at an angle of approximately 5 degrees to the hori zontal (Figs. 3 and 8), while the side surfaces 36b and 39 of respectively the retaining band and shank portion are tapered inwardly in an upward direction at an angle of approximately 10 degrees to the vertical. The latter combination of tapers has been found to very effectively lock the cutting tip element to the tooth proper. It will be understood of course that the cross sectional area of the passageway defined by the band element 30 with respect to the cross sectional area of the shank portion 22 is such that when the band and assembled tip element 26 are driven inwardly along the shank, the band will deform to the extent necessary to provide full wedging coaction between surfaces 36a and 37 and between surfaces 36b and 39. It will also be seen that as the tooth cuts into the material to be excavated, the shoulders 28 on the tip element 25 engage front surface 38 on the collar member 30 on opposite sides of the latter, and continually urge the aforementioned tapered surfaces into wedging coaction, to thus insure maintenance of the assembled condition of the parts of the tooth, as well as equally distributing the stresses applied to the tooth.

Referring to Figs. 9 and 912, there is shown a modification of the invention wherein the cross sectional configuration of the shank portion 22 of the base 21 of the tooth is reversed so that the fiat abutment surface 44 adapted for engagement with cutting tip element 26 is positioned on the top of the shank while the tapered surfaces 37 and 39 of the shank are disposed on the generally underside of the tooth assembly. In this arrangement the cutting tip element is positioned on top of the shank 22 with the flange portion 32 projecting upwardly thereform, and the band is reversed from its position in the first described embodiment of the invention. In all other respects the modification of Figs. 9 and 9a is generally similar to the first described arrangement of the tooth assembly.

In Figs. 10 and 10a there is shown a further modification of the invention wherein a band element 50 com: prises a generally arcuate-like top wall 52 with inwardly turned flanges 54 at the sides thereof. The cutting tip element 5'6 is of rectangular-like configuration in top plan and is secured as by means of welds 58 to flanges 54 of the band to provide a rigidly fastened, unit assembly of the band and tip parts. The assembly of the Fig. 10 and 10a modification to the shank portion of the base of the tooth and its operation is substantially similar to the first described embodiment of the invention.

In Fig. 11 there is shown a further modification of the invention wherein a lug or head 60 is provided on the inner surface of the band element 30 and is adapted to be received in a recess 62 in the shank portion 22 of the tooth to positively stake the cutting tip and band assem bly to the tooth proper. The latter arrangement may be most effectively used where very high vibration or stress conditions exist in service operation and especially under reverse load conditions to thereby positively insure maintenance of the assembled condition of the separable patts of the tooth. The staking of the band and d shank portions could either be accomplished after the parts of the tooth are in assembled condition, or the head 60 and recess 62 could be preformed in the respective parts and thereafter moved into coacting relationship during assembly of the tooth.

From the foregoing description and accompanying drawings, it will be understood that the invention provides a novel separable digging tooth assembly for excavators, wherein the separable hardened cutting tip of the tooth is maintained in assembled condition with a shank portion of the base of the tooth by means of a detachable band or collar element of comparatively ductile nature, which coacts with the cutting tip and shank portions to securely hold the tip and base parts of the tooth in assembled condition. The invention also provides a digging tooth assembly of the latter-described type, wherein a combination of tapered locking surfaces on the band and shank portions of the tooth assembly are provided for frictionally locking the parts of the tooth in wedged assembled relationship. In addition, the invention provides other novel structural features for a separable tooth assembly for improving the efliciency and usability of the excavating machine with which such tooth assembly is utilized.

The terms and expressions which have been employed are used as terms of description and not of limitation and there is no intention in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the invention claimed.

'1 claim:

1. An excavating tooth comprising in combination, a base member having a shank portion, a separable cutting tip member projecting forwardly from and engaging said portion in generally flat surface-to-surface relationship, a tensionally expanded retaining band member encircling said tip member and said shank portion rearwardly of the forward extremity of the latter to hold said tip and base members in assembled relation, means on said tip and band members for preventing relative lengthwise movement therebetween in both a forward and a rearward direction, said band member and said shank portion comprising complementary tapered surfaces thereon extending lengthwise thereof and coacting in wedging relation to tensionally expand said band member, said base member having a pair of transversely spaced shoulders.

thereon disposed on opposite sides of said shank portion, said band member having a rearwardly facing abutment surface on the upper portion thereof disposed generally intermediate said shoulders and generally forwardly of the latter, said shoulders and abutment surface being adapted for engagement by an associated wedging tool for forcing the interlocked band and tip members outwardly with respect to said shank portion to disassemble said tooth.

2. An excavating tooth in accordance with claim 1, wherein said tip member is of generally plate-like configuration comprising a rearward body section and a forwardly disposed head section, said means comprising a depending lip adjacent the rearward end of said body section disposed in overlapping interlocked relation with the rearward extremity of said band member to prevent relative forward movement of said tip member with respect to said band member and transversely spaced shoulder portions adjacent the forward end of said body section disposed in overlapping interlocked relation with the forward extremity of said band member to prevent relative rearward movement of said tip member with respect to said band member.

3. In a multiple part excavating tooth assembly comprising a base member having a forwardly projecting shank portion, a separable cutting tip member engaging said shank portion in generally flat surface-to-surface relation and extending forwardly therefrom, a tensionally tip and b ase members iii assembled reiatioir si'd retain- "in" elemeni open-ended defining itun'nl-like'com' figuration audbeing disposed rearwardly of the forward extremity of said shank'portiom 'said retaining element i to shzmlg portiori, saiid'base member'h'aj irzig''gaiiroftrarlsversely'sp'qced shoulders thereori' disgosedpn opposite sides of saidlsl anl; portion, said retai ning elei nent and attached 'tip member having :a' rearwardly' facing abutment surface'on'th'e upper portion thereof disposed ge'nerally intermediate said'shoulders 'and'generally foiwazdly of the la tter, said shoulders and abutment surface being adapted for "engagement by an associdted'wedging tool F 'forforcing Ihe integral retaining element and tipmemb'er outwardly with resp'ec't to said shmkiportion to disas- 5 V semblesaidtoorh f; 7

i Refer-eases cit e d in the file of thisi'pdtent UNITEDsTATEs PATENTS 25,654 7 Lee et al. I Oct. 4, 1859 829,906 Blaine Aug. 28, 1906 2,124,230 Hosmerepal.; Ju1y 19, 1938 2,666,272 Everett Jan; 19, 1954 12,688,910 Adair Q Sept. 14, 1954 2,729,902

Lau'nder Jan. 10, 1956 

